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Rudi Kiefer: Earthquakes, tsunamis are a threat near plate boundaries

Rudi Kiefer

Updated:
March 3, 2018, 11:32 p.m.

While discussing climatic change, students respond frequently that they expect increasing numbers of tsunamis like the ones we’ve seen in Japan (2011) and Indonesia (2004). But tsunamis aren’t controlled by the weather.

The Japanese term applies to ocean waves created by an undersea earthquake. Shake a dish tub full of water, and you see ripples. It’s the same on the ocean. When its bottom gets rocked, the ripples spread on the surface. On a deep ocean they travel fast.

A jetliner, moving 500 mph, would barely keep up with the waves. Once they reach shallow water, friction with the ocean floor slows the bottom movement. At the top, the waves keep going and topple over. On the shore, the waves break, water piles up, and an enormous splash wipes away buildings, cars and people who unwittingly stand at the beach watching the event. YouTube shows some disturbing videos of that.

Obviously, areas with houses built near sea level are the most endangered by this. On the U.S. East Coast, barrier islands have nothing but sand dunes to provide some elevation. However, the eastern shores of North America aren’t earthquake prone because there is no plate boundary nearby.

Earthquakes, on land or water, are most common where the tectonic plates, the building blocks of the globe, rub against each other.

In our hemisphere, this makes coastal communities on west coasts vulnerable. Diablo Canyon nuclear plant in California, 7 miles north of Avila Beach and just 10 miles from other beach communities, is a concern. The nuclear disaster at the Fukushima Daiichi Plant in Japan, caused by the 2011 tsunami, sent a clear warning about reactors close to the seashore.

A Feb. 25 article in Forbes Magazine provides soothing news about Edison International’s San Onofre Nuclear Generating Station in San Diego County. It states that engineers are well prepared for an emergency.

SONGS is decommissioned, though, and radioactive waste is being moved off-site. By contrast, Diablo Canyon, 12 miles from San Luis Obispo, is operating. This January, California regulators agreed to close the plant by 2025.

This will leave the tsunami risk with coastal communities in California, and northward all the way to Alaska. Local governments will be well advised to provide plenty of preparation and public education for the next event that can send devastating waves into beachfront housing.

Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.